Packet data connections are emerging in cellular networks in order to provide data transmissions with better resource utilizations. Due to the nature of the packet data traffic, especially in the Internet, users must be able to define different kinds of packet screenings. In GPRS, for example, the user has to pay for downlink packets he receives.
Moreover, it should be possible to charge a packet data traffic according to the connection endpoint identified by a connection endpoint identifier (CEI). This could be used for transmitting advertisements to a network user and charging the transmitting party instead of the user.
Furthermore, if an interworking function is to be established between a packet data network, like the IP network, and an Intelligent Network (IN), it would be desirable implementing an IN interrogation function. Such an IN interrogation function enables an implementation of subscriber-specific network services.
However, in data networks an IN interrogation cannot be triggered by each packet without triggering a huge amount of signaling.